Not applicable.
Not applicable.
1. Field of the Invention
This invention relates to fluid pressure responsive collapsible pin type relief valves and more particularly to a dual piston valve actuator.
2. Description of the Prior Art
Collapsible buckling pin type valves are known in the art; however, I am not aware of a collapsible pin-type actuator body containing dual pistons acting on a pinion in response to system fluid pressure for opening or closing a system valve.
The valve actuator includes a sleeve-like body having flanged ends closed by bolt flanges and having a pair of pistons slidably disposed in respective end portions of the body. The body transversely journals a shaft having a pinion thereon meshing with racks on piston arms projecting toward the opposite piston and in mesh with the pinion. The respective end of the body wall contains an inlet port communicating with respective ends of the valve actuator body and a third inlet port communicating with body between the position of the pistons. A piston rod is slidable through the bonnet of the valve actuator and supports one end of a collapsible pin supported at its other end by a plate supported by a plurality of post means secured to the valve actuator bonnet. Fluid pressure of a predetermined value entering the space between the pistons, collapses the pin at a desired set point to activate the valve and open or close a system valve.
A principal object of this invention is to provide a collapsible pin dual piston-type valve actuator responsive to excessive system fluid pressure or vacuum which separates a pair of pistons and buckles the collapsible pin while simultaneously angularly rotating a control shaft opening or closing a system valve.